Tweco VAF4 Transmig - Manual (Page 72)

TRANSMIG VAF4
SERVICE 4-8 Manual 0-5231
Problem 2 - Inconsistent Wire Feed
!
WArNING
Disengage the feed roll when testing for gas flow by ear.
Wire feeding problems can be reduced by checking the following points.
FAULT CAUSE
1 Feed roller driven by motor in the cabinet
slipped.
Wire spool brake is too tight.
2 Wire spool unwound and tangled. Wire spool brake is too loose.
3 Worn or incorrect feed roller size A Use a feed roller matched to the size you are welding.
B Replace feed roller if worn.
4 Wire rubbed against the misaligned guides and
reduced wire feed ability.
Misalignment of inlet/outlet guides
5 Liner blocked with swarf A Increased amounts of swarf are produced by the wire passing
through the feed roller when excessive pressure is applied to the
pressure roller adjuster.
B Swarf can also be produced by the wire passing through an
incorrect feed roller groove shape or size.
C Swarf is fed into the conduit liner where it accumulates thus
reducing wire feed ability.
6 Incorrect or worn contact tip A The contact tip transfers the weld current to the electrode wire. If
the hole in the contact tip is too large then arcing may occur inside
the contact tip resulting in the wire jamming in the contact tip
B When using soft wire such as aluminium it may become jammed in
the contact tip due to expansion of the wire when heated. A contact
tip designed for soft wires should be used.
7 Poor work lead contact to work piece If the work lead has a poor electrical contact to the work piece then
the connection point will heat up and result in a reduction of power
at the arc.
8 Bent liner This will cause friction between the wire and the liner thus reducing
wire feed ability
Table 4-3 Wire Feeding Problems